Morgulis and Spencer (1) reported that the urinary excretion of creatine was increased in vitamin E-deficient rabbits and that there was no decrease in the urinary creatinine excretion. Goettsch and Brown (2) found that the muscle content of creatine was decreased in vitamin E-deficient rabbits which indicated the creatinuria was at least in part the result of a nonretention or nonutilization o...

Creatine is important for energy metabolism, yet excitable cells such as cardiomyocytes do not synthesize creatine and rely on uptake via a specific membrane creatine transporter (CrT; SLC6A8). This process is tightly controlled with downregulation of CrT upon continued exposure to high creatine via mechanisms that are poorly understood. Our aim was to identify candidate endogenous CrT inhibito...

OBJECTIVE In heart failure, cardiac energy metabolism is compromised. The failing myocardium is characterized by reduced contents of both phosphorylated (phosphocreatine) and non-phosphorylated (free) creatine content as well as decreased energy reserve via creatine kinase (creatine kinase reaction velocity). These changes may contribute to cardiac dysfunction. The purpose of the present study ...

Background Athletes use ergogenic aids in an attempt to increase training-adaptations, which serves to enhance their performance during competition. Creatine monohydrate is one of the most studied ergogenic aids. Although many studies have reported the efficacy and effectiveness of creatine monohydrate supplement manufacturers continually introduce newer forms of creatine into the marketplace. ...

Supplementation with creatine-based substances as a means of enhancing athletic performance has become widespread. Until recently, however, the effects of creatine supplementation on cognitive performance has been given little attention. This study used a new form of creatine--creatine ethyl ester--to investigate whether supplementation would improve performance in five cognitive tasks, using a...

PURPOSE The effects of creatine supplementation on muscle metabolism and exercise performance during a simulated endurance road race was investigated. METHODS Twelve adult male (27.3 +/- 1.0 yr, 178.6 +/- 1.4 cm, 78.0 +/- 2.5 kg, 8.9 +/- 1.1 %fat) endurance-trained (53.3 +/- 2.0 ml* kg-1* min-1, cycling ~160 km/wk) cyclists completed a simulated road race on a cycle ergometer (Lode), consisti...

Creatine is a key regulator of brain energy homeostasis, and well-balanced creatine metabolism is central in healthy brain functioning. Still, the variability of brain creatine metabolism is largely unattended in magnetic resonance spectroscopy (MRS) research. In the human brain, marginal sex differences in creatine levels have been found in the prefrontal cortex. It is however not known to wha...

Although creatine is one of the most widely used nutritional supplements for athletes as well as for patients with neuromuscular disorders, the effects of oral creatine supplementation on endogenous creatine synthesis in humans remains largely unexplored. The aim of the present study was to investigate the metabolic consequences of a frequently used, long-term creatine ingestion protocol on the...